Lighting apparatus with total internal reflection lens and mechanical retention and locating device

ABSTRACT

A lighting apparatus includes a light source having a plurality of light-emitting-diodes and a lens assembly with a lens and a lens holder. The lens includes a body member having an outer surface shaped to provide total internal reflection and an interior open channel extending longitudinally through the body member. The body member has a first end region for accommodating the light source and a second end region that includes a plurality of refractive surface regions positioned around the open channel. The lens holder has a concave interior surface shaped to accommodate the optical body member of the lens and a convex exterior surface. The holder has multiple clips for securing the lens and three or more support members extending from the exterior surface toward the first end.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a division of U.S. application Ser. No.12/420,802, filed on Apr. 8, 2009, entitled “TOTAL INTERNAL REFLECTIONLENS FOR COLOR MIXING,” which claims priority to U.S. Provisional PatentApplication No. 61/105,407 filed Oct. 14, 2008 and entitled “TOTALINTERNAL REFLECTION LENS FOR COLOR MIXING,” which is commonly owned andincorporated by reference herein. This application is also related tocommonly owned U.S. Patent application Ser. No. 12/344,158, filed onDec. 24, 2008, entitled “Light-Emitting Diode With Light-ConversionLayer,” U.S. Provisional Application No. 61/167,761 filed of even dateherewith and entitled “PACKAGE FOR MULTIPLE LIGHT EMITTING DIODES,” andU.S. Patent application Ser. No. 12/420,800 filed of even date herewithand entitled “LIGHTING APPARATUS HAVING MULTIPLE LIGHT-EMITTING DIODESWITH INDIVIDUAL LIGHT-CONVERSION LAYERS.”

BACKGROUND OF THE INVENTION

The present invention relates generally to lighting apparatus and moreparticularly to total internal reflection (TIR) lenses and holders forproviding centered light output with improved brightness and efficiency.

A light-emitting device usually includes a light source and a packagefor supporting the light source and directing, focusing, filtering, orenhancing light emitted from the light source. Some examples of lightsources include a light-emitting diode (LED), an incandescent lamp, asapphire crystal light, and a fluorescent lamp.

An LED is a semiconductor device that emits incoherent narrow-spectrumlight when electrically biased in the forward direction of the p-njunction. This effect is a form of electroluminescence. The color of theemitted light depends on the composition and condition of thesemiconducting material used, and can be infrared, visible ornear-ultraviolet. Advantages of LEDs over other lighting sources includecompactness, very low weight, low power consumption, simple andinexpensive manufacturing, freedom from burn-out problems, highvibration resistance, and an ability to endure frequent repetitiveoperations. In addition to having widespread applications for electronicproducts such as indicator lights and so forth, LEDs also have become animportant alternative light source for various applications whereincandescent and fluorescent lamps have traditionally predominated.

While LEDs are generally monochromatic, LEDs can also be used to producewhite light, for example, using phosphors as light “converters.” In atypical LED-based white light producing device, an LED that produces amonochromatic visible light is encapsulated in a material containing acompensatory phosphor. The wavelength of the light emitted from thecompensatory phosphor is complementary to the wavelength of the lightemitted by the LED such that the wavelengths from the LED and thecompensatory phosphor mix together to produce white light. For instance,a blue LED-based white light source produces white light by using a bluemonochromatic LED and a phosphor that emits a complementary yellow huewhen excited by the blue light. In these devices the amount of thephosphor in the encapsulant is carefully controlled such that a fractionof the blue light is absorbed by the phosphor while the remainder passesunabsorbed. The complementary yellow hue of the light emitted by thephosphor and the unabsorbed blue light mix to produce white light.

Given the importance of LEDs as light sources, particularly LEDs usingmultiple color elements, there is a need for improved lenses and LEDpackaging methods and materials. There is a further need for methods andmaterials that can also reduce light lost at large angles and allow LEDsto produce higher optical performance (Lumens/package) from a smallerpackage or footprint (Lumens/area), which are critical for many lightsource applications.

As demand for better lighting devices continues to increase, it would bedesirable to provide cost effective LED based lighting apparatus havingimproved efficiency and brightness.

BRIEF SUMMARY OF THE INVENTION

In various embodiments, the present invention relates to total internalreflection (TIR) lenses and lens holders and related methods forlighting apparatus applications.

According to embodiments of the invention, a lens assembly has a lensand a lens holder, which can be used with a light source to form alighting apparatus. The lens includes a body member having an outersurface and an interior open channel extending longitudinally throughthe body member. The body member and the interior open channel aresubstantially symmetric with respect to an optical axis, and the outersurface is shaped to provide total internal reflection. The body memberhas a first end region at a first end of the open channel foraccommodating a light source and a second end region opposite the firstend region. The second end region includes a plurality of refractivesurface regions positioned around the open channel.

In various embodiments of the lens assembly, the lens holder has aconcave interior surface shaped to accommodate the optical body memberof the lens and a convex exterior surface. Depending on the embodiments,the lens holder can have different support and positioning features. Insome embodiments, the holder has three or more support members that canfit into registration features in the substrate of the light source. Inother embodiments, the holder can have a bottom opening shaped to fitthe periphery of the substrate. In some embodiments, the supportstructures can be built as an integral part of the lens body. In allthese embodiments, the support members are adapted for centering theoptical body member with respect to the light source and maintaining thelight source in the specified position in relation to the optical bodymember. As a result, brightness and efficiency of the lighting apparatuscan be improved.

According to an embodiment of the invention, a lens assembly includes atotal-internal-reflection (TIR) lens and a lens holder. The lensincludes a body member having an outer surface and an interior openchannel extending longitudinally through the body member. The bodymember and the interior open channel are substantially symmetric withrespect to an optical axis, and the outer surface is shaped to providetotal internal reflection. The body member has a first end region at afirst end of the open channel for accommodating a light source and asecond end region opposite the first end region. The second end regionincludes a plurality of refractive surface regions positioned around theopen channel.

In a specific embodiment of the lens, the interior open channel ischaracterized by a substantially cylindrical sidewall. In an embodiment,the side wall of the interior open channel substantially extends fromone end of the interior channel to the other end along a straight pathwithout bending or angles. In some embodiments, the side wall forms asmall angle, e.g. 1 degree, with the optical axis. In other words, oneend of the interior open channel is slightly larger than the other end.This channel configuration can simplify the manufacturing process, suchas a plastic molding process.

In various embodiments of the above lens assembly, the lens holder has aconcave interior surface shaped to accommodate the optical body memberof the lens and a convex exterior surface. The holder has a firstopening disposed to surround the first opening of the optical bodymember and a second opening opposite the first opening, and the opticalbody member is insertable into the holder through the second opening. Inan embodiment, the holder has three or more support members extendingfrom the exterior surface toward the first opening. The support membersare adapted for centering the optical body member with respect to thelight source and maintaining the light source in the specified positionin relation to the optical body member. In some embodiments, the holderalso has one or more clips in an upper rim region thereof for retainingthe optical body member.

In some embodiments, a lighting apparatus includes the lens assembly asdescribed above and a light source, for example, one or morelight-emitting-diodes (LEDs). In some embodiments, the LEDs may bedisposed on a substrate that has a plurality of registration features.In an embodiment, the support members of the holder are configured tofit into the registration features in the substrate. In an embodiment,the light source has 12 or more light-emitting diodes. In someembodiments, the light source has one or more light-emitting diodes,each of which has a wavelength-shifting material and being adapted toproduce white light.

According to another embodiment, the present invention provides alighting apparatus that includes a lens assembly and a light source. Thelens assembly has a lens and a holder. The lens has an optical bodymember having a first end, a second end opposite the first end, and anouter surface. The optical body member is substantially symmetric withrespect to an optical axis, and the outer surface being shaped toprovide total internal reflection for the light from a source having aspecified position in relation to the first end. The optical body memberalso has an interior open channel extending longitudinally from thefirst end to the second end thereof, the interior open channel beingsubstantially symmetric with respect to the optical axis. The interioropen channel has a first opening at the first end for accommodating alight source and a second opening at the second end. The optical bodymember also has a plurality of curved refractive surface regionsdisposed in the second end thereof and around the second opening of theinterior open channel. In a specific embodiment, the second end has aperipheral flange that is free of curved refractive surface regions, andhas one or more index regions and one or more notches formed therein. Inan embodiment, the optical body member has a concave surface at thesecond end, the plurality of curved refractive surface regions beingformed in the concave surface. In some embodiments, the multiplerefractive surface regions form hexagonal microlenses, each of which hasa curvature and a lateral dimension selected to provide a predeterminedbeam width.

In the above embodiment, the holder is a substantially cylindricalsupport member having a hollow interior region shaped to accommodate theoptical body member. The holder also has a top rim region having one ormore slots for receiving the index regions of the optical body memberand one or more snap clips for fitting to the notches of the peripheralflange region of the optical body member and thereby retaining theoptical body member. Thus, the holder is adapted for centering theoptical body member and maintaining the light source at a predeterminedposition with respect to the optical body member. In an embodiment, thelight source has one or more light-emitting-diodes disposed on asubstrate that includes a plurality of notches. The holder has one ormore cut outs in a side wall, the cut outs configured to allow passageof electrical connectors of the light source.

In another embodiment of the present invention, a lighting apparatusincludes a light source having a plurality of light-emitting-diodesdisposed on a substrate and a lens having protrusions at one end forfitting into the substrate. The lens has an optical body memberincluding a first end, a second end opposite the first end, and an outersurface. The optical body member is substantially symmetric with respectto an optical axis, and the outer surface is shaped to provide totalinternal reflection for light from a source having a specified positionin relation to the first end. The optical body member also has aninterior open channel extending longitudinally from the first end to thesecond end thereof, the interior open channel being substantiallysymmetric with respect to the optical axis. The interior open channelhas a first opening at the first end for accommodating a light sourceand a second opening at the second end. The optical body member furtherhas a plurality of refractive surface regions disposed in the second endthereof and around the second opening of the interior open channel.Furthermore, a plurality of protrusions extend from the first end of theoptical body member and are disposed circumferentially around the firstopening of the interior open channel. The protrusions are arranged tocenter the optical body member and to maintain the optical body memberat a predetermined position with respect to the light source.

In some embodiments, the lighting apparatus described above includes alight source that has four or more light-emitting diodes (LEDs). In anembodiment each of the LEDs has a wavelength-shifting material and isadapted to produce white light.

A further understanding of the nature and advantages of the presentinvention may be realized by reference to the remaining portions of thespecification and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are simplified top view and cross-sectional view,respectively, of an LED-based lighting device having multiple LED dice;

FIG. 2 shows an alternative LED-based lighting device;

FIG. 3A is a simplified cross-sectional view diagram illustrating a lensaccording to an embodiment of the present invention;

FIG. 3B a simplified perspective view of a lens according to anotherembodiment of the present invention;

FIG. 4A is a simplified top view of the lens of FIG. 3B;

FIG. 4B is a simplified cross-sectional view diagram illustrating aportions of the multiple refractive surfaces in the lens of FIG. 4A;

FIG. 4C is a magnified top view of the refractive surfaces in FIG. 4A;

FIGS. 5A-5B are simplified diagrams illustrating a perspective view anda cross-sectional view, respectively, of a lens holder according to anembodiment of the present invention;

FIG. 6 is a simplified cross-sectional view diagram illustrating alighting apparatus according to an embodiment of the present invention.

FIGS. 7A and 7B are simplified perspective view and top view of a TIRlens, respectively, according to another embodiment of the presentinvention;

FIGS. 7C-7G are various additional views of the lens of FIG. 7Aaccording to an embodiment of the present invention;

FIGS. 8A and 8B are simplified perspective views of a lens holderaccording to another embodiment of the present invention;

FIGS. 8C-8I are various additional views of the lens holder of FIG. 8Aaccording to an embodiment of the present invention;

FIG. 9A is a simplified cross-sectional view of a lighting apparatusaccording to another embodiment of the present invention;

FIG. 9B is a 3-dimensional view of partial cross sections of the lensand holder in the apparatus of FIG. 9A showing the lens and the holderin a locked position;

FIGS. 10A is simplified perspective view of a lens according to yetanother embodiment of the present invention;

FIG. 10B is a simplified cross-sectional view of a lighting apparatusincluding the lens of FIG. 10A and a light source according to yetanother embodiment of the present invention; and

FIG. 11A-11D are various additional views of the lens of FIGS. 10A-10B.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention relate to total internal reflectionlenses and lens holders forming light apparatus with improved brightnessand efficiency.

Although finding increasingly wider applications, conventional devicessuffer from many limitations. For example, the color balance of thewhite light or mixed light from multiple colored light sources can varydepending on the position of the light source or an angle from which thelight is viewed, which results in a non-uniform color distribution.Attempts have been made using special mixing lenses to compensate forthe non-uniformity of the color distribution. However, while thevariation may be reduced, the color still varies noticeably depending onthe angle of the emitted illumination, or the angle from which theillumination is received or viewed. Such color non-uniformity cannegatively affect designs for light apparatus such as spot lights andother general lighting applications, and color display technologies suchas active matrix thin film transistor liquid crystal displays (TFTLCDs)in applications such as consumer computer and television monitors,projection TVs, and large advertising displays. One solution to theproblem of color variation is to use a secondary lens with a lightmixing design on the light emitting device. Unfortunately, the secondarylens generally causes a 40% to 50% reduction in light intensity outputby the light emitting device.

In various embodiments, the present invention provides lightingapparatus with total internal reflection (TIR) lenses and lens holdersfor providing centered light output with improved brightness andefficiency.

FIGS. 1A and 1B are simplified top and cross-sectional side views of anLED-based lighting device 100 having multiple LED dice. As shown in FIG.1A, four LED dice 101-104 are disposed in a recess 107 on substrate 106.As shown in FIG. 1B, a light-converting material 105, such as phosphor,is deposited over the LED dice. For example, for a white light device,LED dice 101-104 may be blue LEDs, and light-converting material 105 maybe a yellow phosphor. Additionally, a primary lens 108 may be disposedover the LEDs.

FIG. 2 shows another LED-based lighting device 200 having multiple LEDdice, of which LED dice 221 and 222 are shown. Each LED die has alight-converting material, e.g., 228 and 229, deposited thereon.Lighting device 200 also has a primary lens 230. The light-convertingmaterial, containing a wavelength-shifting material such as phosphor, isdeposited over the top surface of each LED, and the side surfaces of theLED are substantially free of the phosphor-containing material. Thisdeposition process may be performed using a syringe or a needle for eachof the LEDs. Further details of methods for depositing phosphor overindividual LED dice can be found, for example, in U.S. patentapplication Ser. No. 12/344158, filed on Dec. 24, 2008 and entitled“LIGHT-EMITTING DIODE WITH LIGHT-CONVERSION LAYER.”

FIG. 3A is a simplified cross-sectional view diagram illustrating a lensa according to an embodiment of the present invention. In embodiments ofthe present invention, lens 300 is configured to provide collimatedlight with uniform color output. Depending on the embodiments, lens 300can be made of different material, e.g. glass or transparent plasticsuch as PMMA (Polymethylmethacrylate). Of course, other material havingsuitable refractive index and transparency can also be used.

In the embodiment of FIG. 3A, lens 300 has a body member 312, which hasan outer surface region 314 and an interior open channel 316 thatextends longitudinally through body member 312. Optical body member 312and interior open channel 316 are substantially symmetric with respectto optical axis 320. In an embodiment, the outer surface region 314 isshaped to provide total internal reflection of light from a light sourcepositioned below region 330.

As shown in FIG. 3A, lens 300 has a first end region 330 at a first end317 of open channel 316 for accommodating a light source, such aslighting device 200 of FIG. 2 or lighting device 100 of FIG. 1. Lens 300also has a second end region 340 at a second end 318 of open channel 316opposite the first end region 330. The second end region 340 has acircular surface 342 that includes a plurality of refractive regions 344(e.g., microlenses) positioned around second end 318 of open channel316. In some embodiments, lens 300 also has flange 345 at the edge ofthe second end region 340.

In some embodiments, interior open channel 316 is characterized by asubstantially cylindrical sidewall 319. In certain embodiments, thecylindrical sidewall surface extends from the first end 317 to thesecond end 318 of open channel 316 without bending. According to aspecific embodiment, the substantially straight side wall can providemore reflection and better mixing of light in the open channel.Therefore in some embodiments, it is desirable for the open channel sidewall to have no bending or angles. In some embodiments, long and narrowopen channels can provide better light reflection and mixing. Thesubstantially cylindrical side wall 319 can be slightly tapered (e.g., 1degree or less, or 5 degrees or less) such that the opening at first end317 is slightly smaller than the opening at the second end 318.

In certain embodiments, the interior open channel 316 tends to collimatelight in the center region. The total-internal-reflection surface 314 isadapted to prevent light loss, and the multiple refractive surfaceregions 344 operate to distribute light uniformly. In some embodiments,the multiple refractive surface regions 344 in end region 340 of lens300 can have hexagon or honeycomb shapes. The size of the hexagon in thehoneycomb pattern can be optimized experimentally, based on a desiredoutput beam width.

As described above, in certain embodiments, one end of the open channelcan be slightly larger than the other. For example, the cross-sectionalprofile of the cylindrical sidewall 319 can form a small angle, e.g., 1degree, relative to optical axis 320. The slightly expanding openchannel can simplify the process of making the lens. For example, thelens can be manufactured using a plastic molding process, and theslightly slanted sidewall can facilitate the separation of the lens andthe mold.

According to embodiments of the present invention, the outer surface 314of lens 300 is shaped to provide total internal reflection of lightoriginating from a group of LEDs placed in a particular position belowopening 317. In some embodiments, the shape of outer surface 314 can bedescribed by the following equation.

$\begin{matrix}{z = \frac{{cr}^{2}}{1 + \sqrt{1 - {\left( {1 + k} \right)c^{2}r^{2}}}}} & (1)\end{matrix}$where z denotes the longitudinal coordinate (z=0 is the plane of firstend region 330) and r is the radius measured from the optical axis 320,as shown by the coordinates in the upper portion of FIG. 3A. Curvatureparameters k and c can be varied, e.g., based on a particularconfiguration of LEDs, to optimize total internal reflection.

Light from the source entering lens 300 from first end 330 that strikesTIR surface 314 is internally reflected and, therefore, is largelyprevented from escaping out the side of the lens. However, theefficiency of the TIR surface need not be 100%, as absorption by thelens body and surface leakage can reduce the efficiency of the lens. Insome embodiments, lens 300 can have an efficiency of about 70% orhigher. In a specific embodiment, the efficiency of the TIR lens isabout 80-85%.

FIG. 3B a simplified perspective view of lens 350 which is similar tolens 300 in FIG. 3A. Therefore, similar or identical features arelabeled with the same reference numbers as in FIG. 3A, such as TIRsurface 314, flange 345, interior open channel 316, and refractivesurface regions 344. In this particular embodiment, the refractivesurface regions 344 form microlenses that are hexagonal in shape and arearranged in a honeycomb pattern.

FIG. 4A is a simplified top view of lens 350 of FIG. 3B, showing flange345, interior open channel 316, and microlenses 344. FIG. 4B shows across-sectional view of a portion of the microlenses 344, in which amicrolens is shown to have a radius R and a height h. FIG. 4C is amagnified top view of the microlenses, which are shown as hexagonalshaped regions having a lateral dimensional L. According to embodimentsof the present invention, the microlenses can be made to providedifferent beam widths by varying the parameters such as R, h, and L. Invarious embodiments, lenses are configured to provide wide, medium, ornarrow beam widths to suit different applications. For example, in oneembodiment, a configuration with R=3.0 mm, h=0.1 mm, and L=1.33 mm isused for a narrow beam having a beam width of about 12-17 degrees; R=2.0mm, h=0.2 mm, and L=1.51 mm is used for a medium beam having a beamwidth of about 20-24 degrees; and R=3.0 mm, h=0.55 mm, and L=3.0 mm isused for a wide beam having a beam width of about 25-30 degrees. Itshould be noted that the selection of the values of the (R, h, L)parameters for shaping a beam width can be largely independent of thevalues of k and c in Equation (1).

FIGS. 5A-5B are simplified diagrams illustrating a perspective view anda cross-sectional view, respectively, of a lens holder according to anembodiment of the present invention. As shown, holder 500 has a concaveinterior surface 502 (shown in FIG. 5B) shaped to accommodate theoptical body member of a lens, such as lens 300 of FIG. 3A or lens 350of FIG. 3B. Holder 500 also has a convex exterior surface 504. In anembodiment of the invention, holder 500 is configured to fit lens 300 ofFIG. 3A, which has first opening 317 and second opening 318. In thiscase, holder 500 has a first opening 506 disposed to surround the firstopening 317 of the lens and a second opening 508 opposite the firstopening, and the optical body member of the lens is insertable into theholder through second opening 508.

In an embodiment, holder 500 has three or more support members 520extending from the exterior surface 504 toward first opening 506. In anembodiment, holder 500 also has one or more clips 512 in an upper rimregion thereof for securing the optical body member of the lens. In aspecific embodiment, each of the support members 520 of the holderincludes an elongated body having two sections with two differentlateral dimensions, shown as 521 and 522, respectively, in FIGS. 5A and5B. Here, support members 520 are adapted for centering the optical bodymember of the lens with respect to a light source in a lightingapparatus and maintaining the light source in the specified position inrelation to the optical body member. For example, the light source maybe an LED package with a substrate that has registration features (e.g.grooves, slots, notches, and indentations) and sections 522 of supportmembers 520 may be shaped to fit into these registration features. Inanother embodiment, registration features on an LED package substratemay include raised features (e.g., bumps), and sections 522 may fit overthese features (for example, section 522 may be hollow at the bottomend).

Holder 500 can be made using a suitable material. In an embodiment,holder 500 is made of a plastic material using a molding process. In aspecific embodiment, the internal surface 502 can be a reflectivesurface with, e.g., a metallic coating or reflective paint, to reflectlight escaped from the side surface of the TIR lens. In otherembodiment, the holder can also be made of a metal containing material.

FIG. 6 is a simplified cross-sectional view diagram illustrating alighting apparatus according to an embodiment of the present invention.As shown, lighting apparatus 600 includes lens 300 or 350 as describedabove in connection with FIGS. 3A-3B and 4A-4C, and lens holder 500 asdescribed above in connection with FIGS. 5A and 5B, and light source630.

Depending on the embodiments, lighting apparatus 600 can employincandescent, sapphire crystal, fluorescent, or LED light sources thatoperate over the range of wavelengths from ultraviolet (UV) to Infrared(IR) which covers the range from about 200 to 2000 nanometers.

In some embodiments, light source 630 includes four LEDs in aconfiguration similar to that described above in connection with FIG. 2.In FIG. 6, two of the four LEDs 602 and 604 are shown disposed on asubstrate 631 that includes notches 632. In this case, each supportmember 520 of holder 500 is shaped to fit into one of the notches 632 insubstrate 631. Additionally, light source 630 also includes a primarylens 606 overlying the LEDs.

In a specific embodiment of lighting apparatus 600, lens 300 isoptimized for a light source having 12 LED dice in a package that alsoincludes a substrate and a primary lens. In this embodiment, lens 300has a height of about 25 mm and a diameter of about 45 mm with a flangeregion about 2.75 mm wide. In one example, the microlenses havedimensions R=3.0 mm, h=0.1 mm, and L=1.33 mm for a narrow beam angle,R=2.0 mm, h=0.2 mm, and L=1.51 mm for a medium beam angle, and R=3.0 mm,h=0.55 mm, and L=3.0 mm for a wide beam angle. Additionally, in thisembodiment, holder 500 has three clips 512.

In the examples described above, lighting apparatus 600 has four LEDs.However, any number of LEDs may be used in a lighting apparatusdepending on the embodiments. For example, a lighting apparatus can have1, 2, 4, 8, 12-16, or more LEDs, depending on the application.

FIGS. 7A and 7B are simplified perspective views of a TIR lens 700according to another embodiment of the present invention. FIG. 7C is asimplified top view of a TIR lens according to yet another embodiment ofthe invention. Lens 700 is similar to lens 300 in FIG. 3A, and similaror identical features are labeled with the same reference numbers as inFIG. 3A, such as TIR surface 314, flange 345, interior open channel 316,and top surface with microlenses 344. In an embodiment, lens 700 has aconcave top surface 747 at the second end of the optical body. In thiscase, the microlenses 344 (e.g., as described above with reference toFIGS. 4A-4C) are formed in the concave surface. In the embodiment ofFIG. 7C, microlenses 344 are also formed in peripheral flange region345. In some embodiments, peripheral flange 345 is free of microlenses.Depending on the embodiment, peripheral flange 345 can have one or moreindexing regions, or tabs, 748 and one or more notches 749 formedtherein for fitting to a lens holder. In some embodiments, a protrudingalignment feature 752 is formed below each notch.

FIGS. 7D-7G are various additional views of lens 700 of FIG. 7Aaccording to an embodiment of the present invention. FIG. 7D is across-sectional view of lens 700 of FIG. 7, in which the concave surfaceis labeled 747 and the protruding alignment feature is labeled 752. FIG.7E is a top view of lens 700, which shows index regions 748 and notches749 for fitting with a holder. FIG. 7F is a magnified view of theportion of FIG. 7C inside circle 740 showing notch 749 in more detail.FIG. 7G is a side view of lens 700 showing notch 749 and protrudingalignment feature is labeled 752, among other features.

In a specific embodiment, lens 700 is optimized for a light sourcehaving a single LED die in a package that also includes a substrate anda primary lens. In this embodiment, lens 700 has a height of about 14 mmand a diameter of about 25 mm with a flange region about 2 mm wide. Inone example, the microlenses have dimensions R=3.0 mm, h=0.1 mm, andL=1.33 mm for a narrow beam angle, R=2.0 mm, h=0.2 mm, and L=1.51 mm fora medium beam angle, and R=3.0 mm, h=0.55 mm, and L=3.0 mm for a widebeam angle. Additionally, in this embodiment, lens 700 has threeindexing regions, each having a width of about 5 mm, and five notches,each having a width of about 2.0 mm and a height of about 0.25 mm. Inanother embodiment, lens 700 has two indexing regions and three notches.

FIG. 8A is a simplified perspective view of a lens holder 800 accordingto another embodiment of the present invention. As shown, lens holder800 has a substantially cylindrical body 851 with a hollow interiorregion 852 shaped to accommodate the optical body member of lens 700.Holder 800 also has a top rim region 854 with one or more slots 855 forreceiving the indexing regions 748 of lens 700. One or more snap clips857 and associated cutouts 858 are shaped to fit to notches 749 andprotruding alignment features 752 of lens 700. FIG. 8B is anotherperspective view of holder 800 from a slightly different view angle,showing opening 874 in the bottom plate 877. Thus, holder 800 isconfigured to secure lens 700 and center the lens and maintain a lightsource (not shown) at a predetermined position with respect to theoptical body member. In an embodiment, holder 800 also has two sidewalls 870 at a slanted angle with respect to the cylindrical body, eachside wall having a clearance 872 for allowing connectors from the LEDdevice (not shown) at the bottom of the holder to extend outside theholder.

FIGS. 8C-8I are various additional views of lens holder 800 of FIG. 8Aaccording to an embodiment of the present invention. FIG. 8C is a topview of lens holder 800 showing various structural details, e.g.,slanted side wall 870, clearance 872, and bottom opening 874. FIG. 8D isa bottom view of holder 800 showing, among other features, slanted sidewall 870, clearance 872, and bottom opening 874. In particular, bottomopening 874 in the holder is shaped for securing an LED-based lightsource.

In a specific embodiment, lens 700 and holder 800 are optimized for alight source having a single LED in a package that includes a substrateand a primary lens. The bottom opening 874 of holder 800 is shaped tofit the peripheral contour of that package, and the height of holder 800is selected so that the primary lens of the LED package fits into thebottom opening of lens 700 to allow effective capture of the light fromthe LED dice. In this embodiment, holder 800 has a height of about 15 mmand a diameter of about 27 mm. In this embodiment, older 800 also hasfive snap clips and two slots for holding lens 700. In anotherembodiment, holder 800 has three snap clips and two slots for holdinglens 700.

FIG. 8E is a side view of holder 800 showing the cylindrical holder body851, slanted sidewall 870, and clearance 872. in the c of the holder.FIG. 8F is a magnified view of circle 860 in FIG. 8E showing details ofclip 857. FIGS. 8G and 8H are two side views of holder 800 from twodifferent viewing angles. FIG. 81 is another cross-sectional view ofholder 800, showing the slanted side walls 870 and clearance 872.

FIG. 9A is a simplified cross-sectional view of a lighting apparatus 900according to another embodiment of the present invention. As shown,lighting apparatus 900 includes lens 700 of FIGS. 7A-7E, holder 800 ofFIGS. 8A-8G, and a light source 930. In an example, light source 930 canbe similar to the LED-based light source 200 described above inconnection with FIG. 2. As shown in FIG. 9A, light source 930 has aprimary lens 960. In a specific embodiment, lighting apparatus 900 mayhave only one LED. However, in other embodiments, two or more LEDs canalso be used.

When lens 700 is inserted into holder 800, index regions 748 align withslots 855, and notches 749 fit into snap clips 857. FIG. 9B is a3-dimensional view of partial cross sections of the lens and holder inthe apparatus of FIG. 9A showing the lens and the holder in a lockedposition. As shown, notch 749 and protruding alignment feature 752 oflens 700 are shaped to fit securely with clip 857 and cutout 858 ofholder 800. In FIG. 9A, the bottom opening 874 of holder 800 is shaped(shown in FIG. 8B) to fit the peripheral contour 935 of light source930. Thus, the holder is adapted for centering the lens and maintainingthe light source at a predetermined position with respect to the lens.

FIGS. 10A is simplified perspective view of a lens 1000 according to yetanother embodiment of the present invention. FIG. 10B is a simplifiedcross-sectional view of a lighting apparatus including lens 1000 of FIG.10A and a light source 1050 according to yet another embodiment of thepresent invention. As shown lens 1000 has similar features to lens 300described above in connection with FIGS. 3A-3B and 4A-4C. Some of thecommon features are labeled with the same reference numbers as in FIG.3A, such as optical body member 312, TIR surface 314, flange 345,interior open channel 316, and microlenses 344, etc.

Additionally, lens 1000 has a number of protrusions 1037 extending fromthe first end 330 of optical body member 312. Protrusions 1037 aredisposed circumferentially around the first opening 317 of the interioropen channel 316, and are arranged to center optical body member 312 andto maintain the optical body member at a predetermined position withrespect to a light source.

In an embodiment, the plurality of protrusions 1037 can be made of thesame material as optical body member 312. In a specific embodiment, theoptical body and the protrusions can be made in a single moldingprocess. In other embodiment, different materials or manufacturingmethods can also be used.

In a specific embodiment, lens 1000 can be used with an LED-based lightsource to form a lighting apparatus. FIG. 10B shows such a lightingapparatus with light source 1050, which may be similar to the LED-basedlight sources described above, and additionally including notches orslots 1052 within substrate 1054. In this example, protrusions 1037 areshaped to fit into notches 1052 so that lens 1000 is held in a desiredalignment in relation to light source 1050. In an embodiment, lens 1000is configured to produce substantially centered projected light when theLEDs in light source 1050 are positioned off the optical axis.

FIG. 11A-11D are various additional views of lens 1000 of FIGS. 10A and10B. Specifically, FIG. 11A is a top view, FIG. 11B is a side view, andFIG. 11C is a bottom view of lens 1000. Additionally, FIG. 11D providesa magnified view of a center portion of the bottom view of FIG. 10C,showing four protrusions 1037 disposed circumferentially around thebottom opening of the lens.

In a specific embodiment, lens 1000 is optimized for a light sourcehaving four LED dice in a package that also includes a substrate and aprimary lens. In this embodiment, lens 1000 has a height of about 18 mmand a diameter of about 35 mm with a flange region about 2 mm wide. Inone example, the microlenses have dimensions R=3.0 mm, h=0.1 mm, andL=1.33 mm for a narrow beam angle, R=2.0 mm, h=0.2 mm, and L=1.51 mm fora medium beam angle, and R=3.0 mm, h=0.55 mm, and L=3.0 mm for a widebeam angle. Additionally, in this embodiment, lens 1000 has fourprotrusions, each having a height of about 1.2 mm and a cross-section ofabout 1.5 mm by 0.6 mm.

While certain embodiments of the invention have been illustrated anddescribed, those skilled in the art with access to the present teachingswill recognize that the invention is not limited to these embodimentsonly. Numerous modifications, changes, variations, substitutions, andequivalents will be apparent to those skilled in the art. Accordingly,it is to be understood that the invention is intended to cover allvariations, modifications, and equivalents within the scope of thefollowing claims.

1. A lighting apparatus, comprising: a light source having a plurality of light-emitting-diodes disposed on a substrate that includes a plurality of registration features; an optical body member having a first end, a second end opposite the first end, and an outer surface, the optical body member being substantially symmetric with respect to an optical axis, the outer surface being shaped to provide total internal reflection for light from the light source having a specified position in relation to the first end, the optical body member further having an interior open channel extending longitudinally from the first end to the second end thereof, the interior open channel being substantially symmetric with respect to the optical axis, the interior open channel having a first opening at the first end for accommodating the light source and a second opening at the second end, the optical body member further having a plurality of refractive surface regions disposed in the second end thereof and around the second opening of the interior open channel; and a holder having a concave interior surface shaped to accommodate the optical body member and a convex exterior surface, the holder having a first opening disposed to surround the first opening of the optical body member and a second opening opposite the first opening , wherein the optical body member is insertable into the holder through the second opening, the holder having three or more support members extending from the exterior surface toward the first opening, each support member being configured to fit into one of the plurality of registration features in the substrate, the support members being adapted for centering the optical body member with respect to the light source and maintaining the light source in the specified position in relation to the optical body member.
 2. The lighting apparatus of claim 1 wherein the interior open channel is characterized by a substantially cylindrical sidewall extending from the first opening to the second opening of the interior open channel substantially without bending.
 3. The lighting apparatus of claim 1 wherein the multiple refractive surface regions comprise hexagonal microlenses characterized by a curvature and a lateral dimension selected to provide a predetermined beam width.
 4. The lighting apparatus of claim 1 wherein the holder further comprises one or more clips in an upper rim region thereof for retaining the optical body member.
 5. The lighting apparatus of claim 1 wherein each of the support members of the holder comprises an elongated body having two sections characterized by two different dimensions, respectively.
 6. The lighting apparatus of claim 1 wherein the light source comprises 12 or more light-emitting diodes (LEDs).
 7. The lighting apparatus of claim 1 wherein the light source comprises one or more light-emitting diodes (LEDs), each of which has a wavelength-shifting material and being adapted to produce white light.
 8. The lighting apparatus of claim 1 wherein the light source comprises one or more light-emitting diodes (LEDs) disposed on a substrate that includes a plurality of notches, and wherein each support member of the holder is configured to fit into one of the plurality of notches in the substrate.
 9. The lighting apparatus of claim 1 wherein a side wall of the interior open channel forms an angle of approximately 1 degree with respect to the optical axis.
 10. The lighting apparatus of claim 1 wherein wherein the multiple refractive surface regions comprise hexagonal microlenses in a honeycomb arrangement. 